/**
 * Copyright (C) 2009 - 2013 SC 4ViewSoft SRL
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.android.settings.audio.peq.peq.achart;

import com.android.settings.audio.peq.peq.achart.chart.AbstractChart;
import com.android.settings.audio.peq.peq.achart.chart.RoundChart;
import com.android.settings.audio.peq.peq.achart.chart.XYChart;
import com.android.settings.audio.peq.peq.achart.renderer.DefaultRenderer;
import com.android.settings.audio.peq.peq.achart.tools.Pan;
import com.android.settings.audio.peq.peq.achart.tools.PanListener;
import com.android.settings.audio.peq.peq.achart.tools.Zoom;
import com.android.settings.audio.peq.peq.achart.tools.ZoomListener;

import android.graphics.RectF;
import android.view.MotionEvent;

/**
 * The main handler of the touch events.
 */
public class TouchHandler implements ITouchHandler {
    /** The chart renderer. */
    private DefaultRenderer mRenderer;
    /** The old x coordinate. */
    private float oldX;
    /** The old y coordinate. */
    private float oldY;
    /** The old x2 coordinate. */
    private float oldX2;
    /** The old y2 coordinate. */
    private float oldY2;
    /** The zoom buttons rectangle. */
    private RectF zoomR = new RectF();
    /** The pan tool. */
    private Pan mPan;
    /** The zoom for the pinch gesture. */
    private Zoom mPinchZoom;
    /** The graphical view. */
    private GraphicalView graphicalView;

    /**
     * Creates a new graphical view.
     *
     * @param view the graphical view
     * @param chart the chart to be drawn
     */
    public TouchHandler(GraphicalView view, AbstractChart chart) {
        graphicalView = view;
        zoomR = graphicalView.getZoomRectangle();
        if (chart instanceof XYChart) {
            mRenderer = ((XYChart) chart).getRenderer();
        } else {
            mRenderer = ((RoundChart) chart).getRenderer();
        }
        if (mRenderer.isPanEnabled()) {
            mPan = new Pan(chart);
        }
        if (mRenderer.isZoomEnabled()) {
            mPinchZoom = new Zoom(chart, true, 1);
        }
    }

    /**
     * Handles the touch event.
     *
     * @param event the touch event
     */
    public boolean handleTouch(MotionEvent event) {
        int action = event.getAction();
        if (mRenderer != null && action == MotionEvent.ACTION_MOVE) {
            if (oldX >= 0 || oldY >= 0) {
                float newX = event.getX(0);
                float newY = event.getY(0);
                if (event.getPointerCount() > 1 && (oldX2 >= 0 || oldY2 >= 0) && mRenderer.isZoomEnabled()) {
                    float newX2 = event.getX(1);
                    float newY2 = event.getY(1);
                    float newDeltaX = Math.abs(newX - newX2);
                    float newDeltaY = Math.abs(newY - newY2);
                    float oldDeltaX = Math.abs(oldX - oldX2);
                    float oldDeltaY = Math.abs(oldY - oldY2);
                    float zoomRate = 1;

                    float tan1 = Math.abs(newY - oldY) / Math.abs(newX - oldX);
                    float tan2 = Math.abs(newY2 - oldY2) / Math.abs(newX2 - oldX2);
                    if (tan1 <= 0.25 && tan2 <= 0.25) {
                        // horizontal pinch zoom, |deltaY| / |deltaX| is [0 ~ 0.25], 0.25 is
                        // the approximate value of tan(PI / 12)
                        zoomRate = newDeltaX / oldDeltaX;
                        applyZoom(zoomRate, Zoom.ZOOM_AXIS_X);
                    } else if (tan1 >= 3.73 && tan2 >= 3.73) {
                        // pinch zoom vertically, |deltaY| / |deltaX| is [3.73 ~ infinity],
                        // 3.732 is the approximate value of tan(PI / 2 - PI / 12)
                        zoomRate = newDeltaY / oldDeltaY;
                        applyZoom(zoomRate, Zoom.ZOOM_AXIS_Y);
                    } else {
                        // pinch zoom diagonally
                        if (Math.abs(newX - oldX) >= Math.abs(newY - oldY)) {
                            zoomRate = newDeltaX / oldDeltaX;
                        } else {
                            zoomRate = newDeltaY / oldDeltaY;
                        }
                        applyZoom(zoomRate, Zoom.ZOOM_AXIS_XY);
                    }
                    oldX2 = newX2;
                    oldY2 = newY2;
                } else if (mRenderer.isPanEnabled()) {
                    mPan.apply(oldX, oldY, newX, newY);
                    oldX2 = 0;
                    oldY2 = 0;
                }
                oldX = newX;
                oldY = newY;
                graphicalView.repaint();
                return true;
            }
        } else if (action == MotionEvent.ACTION_DOWN) {
            oldX = event.getX(0);
            oldY = event.getY(0);
            if (mRenderer != null && mRenderer.isZoomEnabled() && zoomR.contains(oldX, oldY)) {
                if (oldX < zoomR.left + zoomR.width() / 3) {
                    graphicalView.zoomIn();
                } else if (oldX < zoomR.left + zoomR.width() * 2 / 3) {
                    graphicalView.zoomOut();
                } else {
                    graphicalView.zoomReset();
                }
                return true;
            }
        } else if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_POINTER_UP) {
            oldX = 0;
            oldY = 0;
            oldX2 = 0;
            oldY2 = 0;
            if (action == MotionEvent.ACTION_POINTER_UP) {
                oldX = -1;
                oldY = -1;
            }
        }
        return !mRenderer.isClickEnabled();
    }

    private void applyZoom(float zoomRate, int axis) {
        zoomRate = Math.max(zoomRate, 0.9f);
        zoomRate = Math.min(zoomRate, 1.1f);
        if (mPinchZoom != null && zoomRate > 0.9 && zoomRate < 1.1) {
            mPinchZoom.setZoomRate(zoomRate);
            mPinchZoom.apply(axis);
        }
    }

    /**
     * Adds a new zoom listener.
     *
     * @param listener zoom listener
     */
    public void addZoomListener(ZoomListener listener) {
        if (mPinchZoom != null) {
            mPinchZoom.addZoomListener(listener);
        }
    }

    /**
     * Removes a zoom listener.
     *
     * @param listener zoom listener
     */
    public void removeZoomListener(ZoomListener listener) {
        if (mPinchZoom != null) {
            mPinchZoom.removeZoomListener(listener);
        }
    }

    /**
     * Adds a new pan listener.
     *
     * @param listener pan listener
     */
    public void addPanListener(PanListener listener) {
        if (mPan != null) {
            mPan.addPanListener(listener);
        }
    }

    /**
     * Removes a pan listener.
     *
     * @param listener pan listener
     */
    public void removePanListener(PanListener listener) {
        if (mPan != null) {
            mPan.removePanListener(listener);
        }
    }
}